1. Technical Field
The present invention relates to a seat apparatus for an automobile, in which a seat is slid in forward and rear directions thereof such that an automobile passenger can easily get into and get out of a rear seat, and in particular relates to improvement in structure in which a seat is folded forward and a back face thereof is used as a table.
2. Background Art
The above seat apparatus for an automobile is conventionally called a xe2x80x9cwalk-in seatxe2x80x9d. As such a seat apparatus, there has been provided one in which, when a front seat in a two-door car or a backrest of a second seat in a car having four or more-doors, such as a one-box car, a minivan or the like are inclined forward, engagement between a seat cushion of the seat and a slide rail supporting the seat cushion is released and the seat is moved forward so that a passenger can get into and get out of a seat positioned rearward of the seat. Also, as a recent seat apparatus for an automobile, there is provided one with a high level of convenience in which a backrest is further foldable forward from the above-described state so as to be substantially horizontal so that the back face of the backrest can be used as a table or a floor surface for a baggage compartment.
In the seat apparatus for an automobile as in the above, since a lock of the slide rail is unlocked by inclining the backrest forward, it is difficult to use the back face of the backrest as a table or a floor of a baggage compartment due to movement of the backrest during use. For this reason, in the conventional seat apparatus for an automobile, two kinds of hinge structures for rotatably connecting the seat cushion and the backrest (seatback) of the seat to each other are respectively provided for a passenger to get into and get out and for setting a table (or baggage compartment floor). In a case in which the backrest is inclined forward using the hinge structure for the table (or baggage compartment floor), the system is employed such that the engagement between the seat cushion and the slide rail is maintained. Therefore, there is a problem in that the weight of the seat apparatus for an automobile and the number of parts are increased.
In view of the above, an object of the present invention is to provide a seat apparatus for an automobile which allows engagement and disengagement between a seat cushion and a slide rail by using one hinge structure.
According to an aspect of the present invention, there is provided a seat apparatus for an automobile comprising: a seat cushion which is movable between a sitting position and a position for getting into and getting out of the automobile, the position is remote forward or rearward from the sitting position; a guide device for guiding the seat cushion between the sitting position and the position for getting into and getting out of the automobile; a backrest which is rotatably connected to the seat cushion via a hinge structure; a locking mechanism which causes the seat cushion to engage and disengage with the guide device, and a lock switching device is provided on the seat cushion and the backrest. The lock switching device releases an engagement between the seat cushion and the guide device performed by the lock mechanism and when the backrest is inclined forward to the seat cushion at a predetermined angle, and engages the seat cushion and the guide device with each other when the backrest is further inclined forward so as to be substantially horizontal.
In the seat apparatus for an automobile constructed in the above, since the engagement of the seat cushion by the lock mechanism is released by inclining the seat back forward at the predetermined angle, a passenger can get into and get out of a seat, for example, on the rear side of the seat cushion by moving the seat cushion relative to the guide device. Then, in a case in which the seat back is further inclined forward so as to be substantially horizontal and the back face of the seat back is used as a table or a baggage compartment floor, since the seat cushion is engaged with the guide device again, the seat cushion is prevented from being moved in use thereby achieving convenience in use. Furthermore, since engagement and disengagement of the seat cushion can be performed by one hinge structure, the number of parts can be decreased and the weight and manufacturing cost of the seat apparatus can be reduced.
Specifically, the lock switching device may comprise a cam which is provided coaxially with a rotating shaft of the backrest and an arm whose intermediate portion is rotatably provided at the backrest. In this case, one end portion of the arm slidably contacts with the cam and the other end portion thereof is connected to the lock mechanism. The cam rotates the arm when the seat back is inclined forward at a predetermined angle, and it allows rotation of the arm in the reverse direction when the seat back is further inclined forward so as to be substantially horizontal. For example, such a structure can be employed such that, when the backrest is inclined forward at a predetermined angle, a large diameter portion of the cam pushes the one end portion of the arm to rotate it. Then, when the large diameter portion of the cam passes through the arm, the arm is rotated in the reverse direction by a biasing force of the lock mechanism, for example. Thereby, the lock mechanism connected to the other end portion of the arm is actuated, so that disengagement between the seat cushion and the guide portion and re-engagement therebetween are performed sequentially.